Come on people just because naruto did rasenshuriken multiple times against pain, doesn't mean he will against kakashi, there are more techs that can be used in sm. Plus people are seriously relying on kamui too much. And Naruto knows kakashi can use kamui, do you think he will charge in without a plan... 2 words.. Shadow clones. He can use shadow clones for distractions. Just because he has stronger attacks, doesn't mean that a normal rasengan wouldn't do the job if kakashi gets hit with it. Plus Naruto sense danger quicker in sm.